Method for ensuring a secure NFC functionality of a wireless mobile communication device and wireless mobile communication device having a secure NFC functionality

• US 8,238,823 B2
• Filed: 02/02/2006
• Issued: 08/07/2012
• Est. Priority Date: 02/09/2005
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Gamand, Patrice, Maugars, Phillipe
• Primary Examiner(s): Urban, Edward
• Assistant Examiner(s): FLEMING-HALL, ERICA L
• Application Number:
  US11/815,767
• Publication Number:
  US 20080188178A1
• Time in Patent Office: 2,378 Days
• Field of Search: 455/41.1, 455/41.2
• US Class Current: 455/41.1
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 7/34 Parallel operation in networks using both storage and other dc sources, e.g. providing buffering H02J7/14 takes precedence
• CPC Class Codes: H04M 1/72412 using two-way short-range wireless interfaces
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: H04W 52/0277 according to available power supply, e.g. switching off when a low battery condition is detected
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

The invention provides a method for ensuring a secure NFC functionality of a wireless mobile communication device comprising the steps of detecting the charge state of a first energy source (1) which supplies the voltage for operating the wireless mobile communication device (S1); switching off the first energy source and switching on a second energy source (2), if the detected charge state of the first energy source (1) falls below a threshold (S2); detecting the charge state of the second energy source (2), if an external NFC signal is received (S3); charging of the second energy source via voltage induced by a received NFC signal to allow at least one secure NFC transaction, if the detected charge state of the second energy source (2) is below a threshold (S4). Furthermore the invention provides a wireless mobile communication device having a secure NFC functionality, which is always ready for operation of at least the secure NFC functionality.

Claims

1. A method of ensuring a Near Field Communication (NFC) functionality of a wireless mobile communication device, the method comprising:

detecting a charge state of a first energy source which supplies a voltage for operating the wireless mobile communication device;

switching off the first energy source and switching on a second energy source, if the detected charge state of the first energy source falls below a first threshold;

detecting a charge state of the second energy source that maintains at least the NFC functionality of the wireless mobile communication device, when the wireless mobile communication device receives an external NFC signal; and

charging the second energy source via voltage induced by the received external NFC signal to perform at least one NFC transaction, if the detected charge state of the second energy source is below a second threshold.

2. The method according to claim 1, further comprising:

charging the first energy source via the voltage induced by the received external NFC signal after the second energy source is completely charged.

3. The method according to claim 1, further comprising:

pre-charging the second energy source at the time of power-up of the wireless mobile communication device so as to maintain the NFC functionality when the first energy source has been switched off or has insufficient voltage to operate the wireless mobile communication device.

8. The method according to claim 1, wherein the first threshold is defined as the charge state of the first energy source.

9. The method according to claim 1, wherein the first threshold is defined according to a stand-by condition.

10. The method according to claim 1, wherein the second threshold is a charge state value necessary for allowing the at least one NFC transaction to answer the received external NFC signal.

11. The method according to claim 1, wherein the second threshold is a charge state value necessary to perform more than one NFC transaction, wherein each NFC transaction comprises at least a pair of the received external NFC signal and a corresponding NFC answer signal.

4. A wireless mobile communication device having a Near Field Communication (NFC) functionality comprising:

an antenna means that receives and sends NFC signals;

a NFC circuit that provides a NFC functionality for the wireless mobile communication device;

a first energy source that supplies power to the wireless mobile communication device;

a second energy source that supplies power to the NFC circuit to maintain at least the NFC functionality of the wireless mobile communication device;

a control means that monitors the charge state of the first energy source, switches off the first energy source, and switches on to the second energy source if the monitored charge state of the first energy source falls below a threshold;

a detecting means that detects the charge state of the second energy source, wherein voltage induced by an external NFC signal received by the antenna means charges the second energy source if the detected charge state the second energy source is not sufficient to allow at least one NFC transaction.

5. The wireless mobile communication device according to claim 4, further comprising:

switching means to switch the charging operation via voltage induced by an external NFC signal from the second energy source to the first energy source after the second energy source is completely charged.

6. The wireless mobile communication device according to claim 4, wherein the second energy source has a sufficiently fast recharging characteristic that the at least one NFC transaction is performed without a noticeable delay after charging the second energy source fit is faster chargeable than the first energy source.

7. The wireless mobile communication device according to claim 4, wherein the second energy source is an integrated micro battery having sufficient capacity to power a NFC circuit.

12. The wireless mobile communication device according to claim 4, wherein the control means is a power management unit (PMU) chip.

13. The wireless mobile communication device according to claim 4, wherein the second energy source is located on a passive companion chip.

14. The wireless mobile communication device according to claim 13, wherein the passive companion chip also performs antenna adaptation and supply decoupling.

15. The wireless mobile communication device according to claim 7, wherein Power Integrated Circuit (PIC) technology is used to fabricate the integrated micro battery.

16. The wireless mobile communication device according to claim 4, wherein a power management unit (PMU) detects the charge state of the second energy source.

17. The wireless mobile communication device according to claim 4, wherein a detection line signal (Vsense) indicates the charge state of the second energy source.

18. The wireless mobile communication device according to claim 4, wherein the first energy source has a much larger capacity than the second energy source.

19. The wireless mobile communication device according to claim 18, wherein fully recharging the first energy source takes much more time than fully recharging the second energy source.

20. The wireless mobile communication device according to claim 4, wherein the second energy source only supplies power to the NFC circuit.